1. Field of the Invention
This invention relates to a method for treating waste fluids containing organic contaminants to solidify the waste fluid to facilitate disposal; and more particularly relates to the forming of a substantially non-flowable matrix from an aqueous waste fluid containing organic contaminants.
2. Prior Art
One of the major problems facing cities, chemical manufacturers, and industries using various chemicals is waste disposal. This problem can generally be divided into three major categories: solidification of fluid waste, disposal of waste by land burial, and remedial action around existing disposal sites which are now leaking.
The use of finely divided or porous solid materials to solidify fluid wastes and spills is well known. Generally, the purpose of solidification is to aid in the disposal of fluid wastes or spills. Among the materials which have been used for solidification are cement, kiln dust, fly ash, soil, and sawdust. These materials have numerous disadvantages. The volume of solidified waste is usually four to five times the volume of the original waste. Additionally, these dusts and the like generally have no specific affinity for one component of the waste relative to another and, even after solidification, liquid components may leach from the waste. Liquid wastes containing five percent (5%) or more of organic contaminants also disrupt the cementatious reactions that help stabilize cement and kiln dust waste products.
These current techniques of waste solidification generally physically trap the organic waste in a solid matrix. When the solid matrix is breached, the organic waste is released unabated to the ground water. Another problem that plagues this method of waste disposal is that during the solidification process, the liquid phase and the solidification medium have a tendency to separate. This renders the method ineffective at stabilizing the waste. One method that has been reported for overcoming this problem is to mix small portions of bentonite with portland cement; this eliminates the aqueous phase separation problem. The bentonite, however, does not adsorb the organic waste. This technology still suffers from the inadequacy of not binding the organic waste other than by physically trapping it.
Prior art of which applicant is aware which relates to solidification of fluid waste are as follows:
British Pat. No. 1,280,373 to Davies et al describes the separation of an oil from an emulsion. Several methods are enumerated for forming the emulsion into two layers for evaporation of the aqueous layer. One of these methods utilizes a mixture of surface-active clay and a polyelectrolyte. First the surface-active clay and then a polyelectrolyte is added to the emulsion. Bentonite is described as a particularly suitable clay. Polyamides are described as particularly suitable polyelectrolytes.
U.S. Pat. No. 3,274,784 to Shock et al, describes a method for the disposal of radioactive waste. This is accomplished by forming a solidifiable composition containing the radioactive waste in the form of a solution or slurry in water and mixing with clay minerals, lime and caustic present in proportions to provide a solid mass on standing. The radioactive wastes contain fissionable products such as strontium, cesium, ruthenium, etc. The preferred clay is calcium montmorillonite. Bentonite was found to require temperatures too high for solidification to take place. Natural clays may also be used.
U.S. Pat. No. 3,948,770 to Goodrich et al describes the use of an anionic polyelectrolyte and a sodium or a calcium montmorillonite clay to effectively separate water oil droplets in sea water.
U.S. Pat. No. 4,033,764 to Colegate et al describes scavenging metal ions from solution by means of a complexing agent comprised of an inorganic substrate, such as a clay mineral, with covalent organic molecules, such as onium compounds, chemically bonded to the substrate.
U.S. Pat. No. 4,149,968 to Kupiec, describes the use of bentonite clays and portland cement in aqueous solutions containing polluting materials, e.g. metallic ions, to form a solid mass.
Japanese No. 015979 to Koyo Kasei KK, describes the detoxification of PCB-containing waste water by mixing the waste water with diatomaceous earth, bentonite or other clay which has been made lipophilic, and then mixing with cement, water, and aggregate. In the method, less than 20% PCB waste liquor, sludges, etc., are mixed with the diatomaceous earth, bentonite, or clay minerals of inorganic fine particles previously made lipophilic by surface treatment. The PCB's are allowed to be adsorbed on the mineral, and then the resulting materials are mixed with cement, water, and aggregate. Diffusing or leaching appears to be reduced. Activated carbon or silica gel may also be used in place of the clay.
Organoclays are well-known in the art, see for example the following U.S. patents:
U.S. Pat. No. 2,531,427 to Hauser; PA1 U.S. Pat. No. 2,966,506 to Jordan; PA1 U.S. Pat. No. 3,422,185 to Kuritzkef; PA1 U.S. Pat. No. 3,974,125 to Oswald; PA1 U.S. Pat. No. 4,081,496 to Finlayson; and PA1 U.S. Pat. No. 4,105,578 to Finlayson et al
None of these aforementioned references teach or suggest the use of these organoclays to immobilize organic contaminants to facilitate their disposal.